Transmission tower



July 11, 1933.

I. w. MARSHALL 1,917,594

July 11, 1933. w sH L 1,917,594

TRANSMI S S I QN TOWER Filed'Sept. 26, 1931 2 Sheets-Sheet 2 I .4 14 '39 4 F 14 L, "E i 1 F 7 1 71 I '8 E W QM, a. M X5, flamggmdcM Patented July 11, 1933 IRA W. MARSHALL, OF PITTSBURGH, PENNSYLVANIA,

A8516 3, TO BLAVLKNOX G01- PANY, OF BLAWNOX, PENNSYLVANIA, A COEPGHATIGN NEW' TRANSMISSION TOVJER Application filed September 26, 1931. Serial Ito. 565,594.

This invention relates generally to transmission towers for supporting electric conductors carrying high voltages. The tower is particularly adapted for supporting the conductors of a number of circuits.

In the accompanying drawings, which illustrate in a somewhat diagrammatic manner several embodiments of my invention,

Figure 1 is a front elevation of a transmission tower showing the manner of supporting the electric conductors;

Figure 2 is a side elevation;

Figure 3 is a partial front elevation of a modified form of tower, the lower portion of the tower being broken away;

Figure 4 is a front elevation of another modified tower of the type which has two cross-arms;

Figure 5 is a sectional plan taken in a plane corresponding to the line VV of Figure 4; and

Figure 6 is a sectional plan taken in a plane corresponding to the line VIVI of Fig ure 4:.

Referring more particularly to Figures 1 and 2 of the accompanying drawings, there is illustrated in a diagrammatic manner a transmission tower built of structural shapes, such as angle irons welded or otherwise secured to form the tower. The tower comprises a body A which is of truncated pyramidal shape and is reinforced by braces 2. The body is supported on four legs B, each of which is of triangular pyramidal shape, the legs being reinforced by braces 3.

A wedge-shaped head C has its base 4 resting on and secured to the upper side of the body A, the head being reinforced by braces 5. The sides 6 of the head meet in a line 7 indicated in Figure 2, the line 7 being referred to herein as the apex of the head. The apex 7 of the head lies in a vertical plane extending through the middle of the tower parallel to the conductors D supported by strings of insulators 8 secured to a crossarm E.

A wedge-shaped support 10 is secured to the middle of the underside of the crossarm, the base 11 of the wedge being secured to the cross-arm so that the apex of the wedge extends downwardly and rests on and is connected to the apex 7 of the wedge-shaped head C. The cross-arm E is further connected to the tower by upwardly diverging struts 12 lying on opposite sides of the head and connecting the ore" -arm to the body I of the tower, the stri cs being reinforced by braces 13. The cross-arm is also provided with wedge-s raped supports 14 which may be used for sir porting ground wires (not shown).

In a tower for supporting electric conductors carrying high voltages, it is necessary to provide suflicient clearance between the conductors and the tower proper to prevent leakage of current or the establishment of an are between the conductors and the tower. \Vith higher voltages, it is necessary to suspend the conductors from longer strings 8 of insulators, and since the conductors sway in the wind, it is necessary to provide sufficient clearances between the conductors and the tower, so that even when the conductors are swayed to a considerable extent by the wind, there will be no danger of current leakage or formation of arcs.

Transmission towers of the type herein described have a heat the rides of which taper upwardly so that the cross-arm may be supported at its center on the narrow upper por tion or apex of the head. The struts 12 diverge upwardly a: d outwardly from the body of toe tower so as to provide a space 15 on each side of the'head which is surlicicntly large so that a conductor hung from a long strin of insulators will have suflicient clearance, even though it is swayed by the wind, so that ther l be no arcing or current leal' age. The co. ruction of the tower herein described is such tat least one conductor D may be suspended in each of the spaces 15. so that there are two conductors supported immediately over the tower instead of nlv one, as has been the case with most towers of the type heretofore known. Additional conductors D may be suspended from the crossarm outside of the struts 12 as desired, the drawings showing cross-arms for suspending six conductors. The head C which supports the cross-arm is symmetrically arranged with respect to the body and legs of the tower, so that the cross-arm may be supported at its center by the head and be further reinforced by the struts 12. The tower is particularly adapted for suspending an even number of conductors on each cross-arm, since spaces are provided for suspending two conductors directly over the tower between the head and struts 12, and additional conductors may be suspended from the cross-arm outside of the struts.

The tower illustrated in Figure 3 is similar to the tower of Figures 1 and 2, except that the center of the cross-arm E is secured directly to the apex 7 of the head G instead of being provided on its underside with a wedge 10, as illustrated in Figures 1 and 2. The

construction illustrated in Figures 1 and 2 is preferred over the construction illustrated in Figure 3 where the conductors carry very high voltages. By supporting the cross-arm E on the wedge 10, as shown in Figures 1 and 2, a wider space 15 is provided so that a long or string of insulators may be used for suspending the conductors and yet suflicient clearance is provided between the conductor and tower so that arcing or current discharge will not occur.

In Figures 4, 5 and 6, a tower having two cross-arms is illustrated. Each of the crossarms E and F is of the trussed construction illustrated in the drawings, particularly Figures 5 and 6, each cross-arm carrying six conductors D. The lower cross-arm E is supported in the same manner as shown in Figure 1, and the upper cross-arm F is supported at its center by a post 16 reinforced by braces 17 and connected at its ends to the cross-arms E and F. The upwardly diverging struts 12 connect each of the cross-arms to the body A of the tower, as previously described. Whether one or more cross-arms are supported from each tower, the arrangement is such that two conductors may be suspended from each cross-arm directly over the tower.

I have illustrated and described several embodiments of my invention. It is to be understood, however, that the invention may be otherwise embodied within the scope of the following claims.

I claim:

1. A transmission tower for electric conductors, comprising a body, a wedge-shaped head supported on the body and lying in the middle plane of the tower parallel to the con ductors, a cross-arm supported by the head, and an upwardly diverging strut on each side of the head connecting the body and cross-arm and providing a free space for suspending a conductor below the cross-arm between each strut and the head of the tower.

2. A transmission tower for electric conductors, comprising a body, a wedge-shaped head supported on the body, the apex of the head lying in a vertical plane extending through the middle of the tower parallel to the conductors, a cross-arm supported by the head, and an upwardly diverging strut on each side of the head connecting the body and cross-arm and providing a free space for suspending a conductor below the cross-arm be tween each strut and the head of the tower.

3. A transmission tower for electric conductors, comprising a body of truncated pyramidal shape, a wedge-shaped head supported on the body, the apex of the head lying in a vertical plane extending through the middle of the tower parallel to the conductors, a cross-arm supported by the head, and an upwardly diverging strut on each side of the head connecting the body and cross-arm and providing a free space for suspending a con ductor below the cross-arm between each strut and the head of the tower.

4. A transmission tower for electric conductors, comprising a body, a wedge-shaped head supported on the body, the apex of the head lying in a vertical plane extending througn the middle of the tower parallel to the conductors, a cross-arm supported at its center by the head, and an upwardly diverging strut on each side of the head connecting the body and cross-arm and providing a free space for suspending a conductor below the crossarm between each strut and the head of the tower.

5. A transmission tower for electric conductors, comprising a body, a wedge-shaped head supported on the body, the apex of the head lying in a vertical plane extending through the middle of the tower parallel to the conductors, a cross-arm having a wedge secured to the underside thereof at the middle of the cross-arm, the apex of said wedge extending downwardly and being supported by and secured to the apex of the head, and an upwardly diverging strut on each side of the head connecting the body and cross-arm and providing a free space for suspending a conductor below the cross-arm between each strut and the head of the tower.

6. A transmission tower for electric conductors, comprising a body, a wedge-shaped head supported on the body, the apex of the head lying in a Vertical plane extending through the middle of the tower parallel to the conductors, a plurality of cross-arms arranged one above the other and supported at their centers by the head, and an upwardly diverging strut on each side of the head connecting each of the cross-arms to the body and providing a free space for suspending a conductor below each cross-arm between each strut and the head of the tower.

7. A transmission tower for electric conductors, comprising a body, a wedge-shaped head supported on the body, the apex of the head lying in a vertical plane extending through the middle of the tower parallel to the conductors, a cross-arm supported at its center on the head, a second cross-arm dispose-d above the first mentioned cross-arm and connected at its center to the center of said first mentioned cross-arm by a post, and an upwardly diverging strut on each side of the head connecting each of the cross-arms to the body and providing a free space for suspending a conductor below each cross-arm between each strut and the head of the tower.

8. transmission tower for electric conductors, comprising a body, a head supported by the body, the head having upwardly converging sides, the vertical planes through the middle of the tower and the middle of the head parallel to the conductors being coincident, a cross-arm supported at its center by the head, and an upwardly-diverging strut on each side of the head connecting the body and cross-arm and providing a free space for suspending a conductor below the crossarm between each strut and the head of the tower.

9. A transmission tower for electric conductors, comprising a body, a wedge-shaped head supported on the body, the apex of the head lying in a vertical plane extending through the middle of the tower parallel to the conductors, a cross-arm supported by the head, and an upwardly diverging strut on each side of the head connecting the body and cross-arm, there being sufiicient free space between each strut and the head for suspending a conductor whereby at least two conductors can be suspended below the crossarm directly over the tower.

10. A transmission tower for electric conductors, comprising a body, a wedge-shaped head supported on the body, the apex of the head lying in a vertical plane extending through the middle of the tower parallel to the conductors, a cross-arm supported by the head, and an upwardly diverging strut on each side of the head connecting the body and cross-arm, there being suihcient free space between each strut and the head for suspending a conductor whereby at least two conductors can be suspended below the cross-arm directly over the tower and at least six conductors can be suspended at the same level from a single tower.

In testimony whereof I have hereunto set my hand.

IRA MARSHALL. 

